1. Field of the Invention
This invention relates to an apparatus that removes adipose tissue in a noninvasive way. More particularly, it relates to a method for the removal of adipose (fat) tissue through the application of compressive and shearing forces on a target area in a patient.
2. Description of the Prior Art
Liposuction is a conventional cosmetic surgical procedure for removing fat (adipose) cells from patients to achieve a desired body shape. Liposuction usually involves an invasive surgical procedure that includes penetrating the skin, melting or shearing adipose tissue, and mechanically removing adipose tissue using a vacuum or other suctioning device.
Liposuction generally achieves the desired effect through the lysis or destruction of the underlying adipose cells. Traditional liposuction is a generally safe but possibly traumatic procedure with a risk of complications. As the cannula is moved through the tissue region, it may damage nerves and/or blood vessels, as well as fatty tissue. Complications include excessive bleeding and a risk of morbidity or mortality. Another potential problem with liposuction is lack of uniformity of the patient's final shape due to irregular removal of fatty tissue, with subsequent contour deformities.
Ultrasound techniques have been coupled to liposuction to enhance the ability to lyse adipose cells in the target region. Ultrasound assisted liposuction (“UAL”) involves introducing a solid stick ultrasound transducer through an incision in the patient's skin and moving the transducer through a fatty tissue region. The transducer emits ultrasonic energy, generally at frequencies of 20-30 kHz, that heats the tissue in the region until necrosis or cavitation or both occurs, thereby rupturing adipose cells in the region. A cannula is then introduced into the tissue region to perform suction, or a hollow transducer may be used that provides suction simultaneously with the delivery of ultrasonic energy.
One shortcoming of UAL techniques is that the transducer may become quite hot during its use. This may result in damage or destruction of tissues adjacent to the target region by overheating or melting. To protect tissue outside the target region, the transducer may be introduced through the skin using an insulated sleeve, although this may require a much larger incision, perhaps about ten millimeters (10 mm) or more in length. In addition, the physician will need to exercise extreme caution and move the transducer continuously to avoid burning tissue. Treatment may also be limited to direct contact between the transducer and the adipose tissue, which may result in non-uniform destruction of fat cells in the target region.
External ultrasound liposuction has been developed as an alternative to invasive techniques. An external ultrasonic generator is used to transmit ultrasound waves through a patient's skin to underlying adipose tissue. The technique is appropriate for only certain parts of the body that are safely spaced apart from tissues and organs such as larger arteries, the heart and the ovaries. Additionally, it may be difficult to achieve the desired effect due to limitations in the process.
A vacuum roller device sold under the trademark Endermologic® purports to decrease the appearance of cellulite and to smooth fat contours. Animal studies have indicated, however, that the device does not change fat or fat cells.
Accordingly, there is a need for improved apparatus and method for destroying subcutaneous adipose cells or other tissue. However, at the time the present invention was made, it was not obvious to those of ordinary skill in this art, in view of the prior art taken as a whole, how the known procedures could be improved.